Known fastener driving apparatuses, such as that disclosed in Willis U.S. Pat. No. 2,994,880, include a barrel having fastener inlet and outlet openings, a retainer mechanism for preventing premature passage of a fastener through the barrel outlet, and a reciprocatorily movable fastener driver that at desired times drives a fastener within the barrel to and from the fastener outlet and into an adjacent workpiece. If the shank of a fastener does not extend substantially parallel to the axis of the barrel as it is driven through and from the barrel, jamming of the apparatus and/or driving of the fastener into the workpiece at an undesirable angle may occur.